Mobile stations have evolved in recent years from simple voice communication devices into powerful mobile computing platforms which can simultaneously collect data from a variety of sources. These mobile stations can combine and processes data from different on-board sensors, transducers, and/or receivers to provide valuable information to the user. In some instances, one or more sensors and/or receivers may provide the mobile station with a capability to determine its position. The ability of mobile stations to accurately determine their position can be useful in the areas of personal productivity, communication, social networking, advertising, e-commerce, and/or other forms of data acquisition. Moreover, the high speed networking capability of these mobile stations can be used in conjunction with their data collection capabilities to offer new mobile applications and services.
In conventional digital cellular networks, position location capability can be provided by various time and/or phase measurement techniques. For example, in CDMA networks, one position determination approach used is Advanced Forward Link Trilateration (AFLT). Using AFLT, a mobile station may compute its position from phase measurements of pilot signals transmitted from a plurality of base stations. Improvements to AFLT have been realized by utilizing hybrid position location techniques, where the mobile station may employ a Satellite Positioning System (SPS) receiver. The SPS receiver may provide position information independent of the information derived from the signals transmitted by the base stations. Moreover, position accuracy can be improved by combining measurements derived from both SPS and AFLT systems using conventional techniques.
In indoor environments where SPS or cellular signals may not be sufficient for accurate position determination, a mobile station may exploit signals from other types of wireless networks, such as Wi-Fi (e.g., IEEE 802.11x standards) or WiMAX (e.g., IEEE 802.16 standards), to derive position information. Conventional position determination techniques used in these other types of wireless networks may utilize range-based position determination techniques. The range-based position determination techniques may estimate distance information using Round Trip Time (RTT) measurements and/or signal strength measurements (e.g., Received Signal Strength Indicator (RSSI)) derived from signals utilized within such networks. The range based position determination may be used for any network device within these networks, such as mobile stations and/or access points (APs) which are placed at unknown positions.
In a variety of mobile applications, users may wish to determine the location of one or more designated targets, which may represent other users, pets, and/or objects of interest, within a predefined group. In some situations, a time history (i.e., tracking a trajectory) of a target may also be desirable. Position information may be determined by mobile stations associated with the designated targets, and subsequently share the position information over a network. Accordingly, such locations of the designated targets may not be visible to a user with the naked eye, but are “known” within the context of the network.
However, conventional approaches for providing position and/or tracking information for one or more targets may be challenging given the limited screen size of mobile stations and the complexity of the information being presented. Conventional approaches may simply overlay the position information of the targets on top of a planar map, which may confuse some users when they attempt to orient the map to their real-world surroundings.
Accordingly, it may be desirable to provide target tracking information to users of mobile stations in a format which is intuitive and can easily allow users to correlate the displayed information to their real-world surroundings.